Metallurgical furnace.



No. 799,745. PATENTBD SEPT.19,1905. 1 P. A. MAGKAY.

METALLUEGICAL I'URNACB.

' APYLICATION FILED APR. 29, 1903.

2 SREETSSHEET l.

No. 799,745. A PATENTED SEPT. 19, 1905.

r. A. marmi.`

METALLURGIGAL FURNAGE. nruorrmn mmm un. 29,1903.

` 2 SHEETS-SHEET 2.

9 Wressea Invennr 'FhihPQA Manuali PHILIP ALEXANDE R. MACKAY, OF

AUSTRALIA.

N E\VCAS'I`LE, NPHV SOUTH \VALES,

METALLURGICAL FURNACE.

vNo. 799,745.

Specification of Letters Patent.`

Patented Sept. 19, 1905.

Application filed April 29, 1903. Serial No. 154.796.

Be it known that I, liumr ALEXANDER Macri-n', a citizen of the United States, residingat Newcastle, in the county of Northumberland and Colony of N ew South lVales, Australia, have invented a certain new and useful Improvement in Metallurgical Furnaces,(Case No. 3.) of which the following isa full, clear, concise, and exact description, reference being had to the accompanyingdrawings, forminga part ol' this specilication.

My invention relates to a metallurgical furnace, and more particularly to a furnace adapted to be used for the treatment of ores in which a distillation process is employed.

My invention is particularly well adapted for use in connection with the treatment of ores containing zine, and l shall describe my invention as adapted for the treatment of such ores.

Zinc oxid is reduced by carbon (C) only after a temperature of about 1,3003' centigrade is reached,thereaction beingZnO-l-CIZn-l-CO; but zine volatilizes at a temperature of less than 1,000C centigrade. Therefore the extraction of zinc is possible only by distillation and condensation.

In order to free zinc ores from water and carbonio acid, it is customary to first treat zinc ores-for instance, ores in which the sultid of zinc (Z115) is present-by calcination or roasting. There is a further reason why sullid ores are roasted preliminary to distillation, which is that it is necessary to reduce by roasting the zine suliid (ZnS) to zinc oxid(ZnO) in order that it may later be acted upon by carbon. There have been a number of processes used to reduce the zinc oxid after this preliminary roasting-such as the old English process, the VSilesian process, and the Belgian process-in all of which the principle has been the same. Taking as an example the Belgian process, it has been the practice to charge clay retorts with a mixture of the roasted and ground oxid and other minerals present and carbon in the form of coalor coke screenings in about equal proportions.

As is well understood by those skilled in the art the ores ot' zinc-such as zincite, calamin, and blende-contain many other substances besides pure compounds of zinc. Thus in addition to zinc sullid blende contains sultids of iron, lead, antimony, and cadmium. These impurities of course are more l or less reduced during the roasting process and are then charged intothe retorts with the zinc oxid. The Zinc ores also frequently contain the precious metals gold and silver. The cha rgcd retorts are then gradually heated. In case it has beendesircd to obtain bar-zize or Zinc-dust the retorts are provided with suitable condenser-s which condense the volatilized zinc which is distilled over.

Zinc oxid is now much used in the arts, and it is the practice to burn zine in air to form fumes ot' oxid of zinc, which fumes are passed through a so-called bag-room, which is a passage-way intercepted by suitable sheets of cloth adapted to collect the powdered oxid of zinc. Such Zinc processes as heretofore carried on have been more or less limited in capacity, due to the difficulties incident to the use of retorts. It is very diiiicult to charge retorts which are of sufiicient size to give satisfactory results. The retorts themselves are sooner or laterdestroyed bythe reactions going on within. Such a retort-furnace is not well adapted for continuous operation.

My invention has for its object the provision of a suitable furnace for'the reduction of roasted zinc ores, which by its construction and mode of operation is peculiarly well adapted for continuous operation and which by its design may be made to accommodate and successfully7 treat large quantities of ore.

The embodiment of my invention, which I shall herein describe,is intended for use where the product to be obtained is zinc oxid rather than metallic zinc. However, I do not wish to limit myself to the use of the furnace for this purpose or in this manner.

My invention will be clearly understood by reference to the accompanyingr drawings, in which- Figure 1 is a. plan view of a. furnace construeted in accordance with my invention, one end being broken away to more clearly reveal the interior construction. Fig. 2 is a crosssectional view taken on line 2 2 ot' Fig. 1. Fig. 3 is a cross-sectional view taken on line 3 3 of Fig. I, and Fig. 4 is a partial cross-seef tional view taken on line4 4 of Fig. 3.

my invention may be built-ot' tire-brick or any suitable refractory material. There are provided two sets of regenerators, each comprising a chamber 5, filled with suitable checker-work in the manner well understood A furnace constructed in accordance withl IOO by those skilled inthe art, and a second chamber6` similarly filled with checker-wmk. The chambers 5 are connected, by means of the passage-ways 7 i', with valving mechanism adapted to admit gas or other suitable fuel to either one or the other of these passage-ways. The chambers 6 6 communicate, by means of the passage-ways 8 8, with valving mechanism adapted to admit air to either one or the other of the regenerator-clmuibers 6. The valving mechanism employed is adapted to cause the admission of fuel and air to the regeneratorchambers on one side of the furnace, the other set of regeneratorchambers being vat that time connected, by means of the passage-wa ys, with a suitable exhaust tlue orchimney. Passage-ways 9 land 10 connect the regeneratorchambers on opposite sides of the furnace, these passage ways including combustionchambers 11 1i, the purpose of which will be hereinafter more fully explained. Interposed between adjacent combustion-chambers 1,1 11 are formed suitable reduction-chambers 12 12` these reduction-chambers being separated from the combustion-chambers by walls as thin as practice will permit. The tunnels 13 13, passing underneath the rows of reductionchambers, are provided with railways 14 14,

upon which cars travel and into which the` residues from the reduction-chambers may be dropped upon opening the doors 15 15, which close the openings 16 16 in the bottoms of the reduction-chambers. Suitable covers 17 17 close openings in the tops of the reductionchambers, through which openings the zinc ores are charged into the reduction-chambers. Passages 18 18 connect the upper parts of the reduction-chambers with the fines 19 19, which lead, in case the furnace is to be operated 'for the direct production of zine oxid, to a combustion-chamber in which the hot volatilized zinc is burned with air to form fumes of zinc oxid. These zinc-oxid fumes are thereafter passed into a bag-room,'where` the zinc oxid is deposited in the manner well understood by those skilled in the art.

The operation of a furnace constructed in accordance with my invention may be described as follows: The regenerative furnace is operated in the well-known manner, in which gas may be supposed to enter through the passage 7 and air through the passage 8, the gas and air passing, respectively, through the checker-work in chambers 5 and 6, being heated by the heat retained in the regenerator-chambers. The gas entering through the chamber 5 flows through the passage-ways 9 to the combustion-chambers 11, while the heated air enters the combustion-chambers through the passage-ways 10. The hot gas and air burn within the combustion-chambers 11 at a very high temperature. The hot products of combustion flow through the passages 9 and 10 on the other side of the furnace to the passive regenerator-chambers 5 and 6, the

-has been blown up with air.

checker-work of which is heated thereby. The products'of combustion pass through the passive regenerator-chambers and the passages 7 and 8 to an uptake-flue. (Not shown.) After the regenerators have been operated fora suitable length of time in this direction the valving mechanism is reversed, so that the gas and air are admitted through the regenerator-chambers, which have just been heated bythe hot products of combustion from the combustion-chambcrs 1l 11. 'l`he lirst set of regenerator-chambcrs are now connected with the uptake-flue, so that they may be heated by the hot products of couibustion issuing from the combustion-chambers.

The operation of the regenerative furnace is well understood by those skilled in the art.l and inand of itself 1 make no claim to the invention thereof.

T he roasted zinc ores, from which it may have been desirable to remove cadmium in the manner described in my copending application, Serial No. 110,9-10.l filed June 9, 1902, are charged, with carbon in convenient form, into the reduction-chambers -12 12. Heat is transmitted through the relatively thin walls from the combastion-chambers 11 11 to the reduction-chambers 12 12. r1`he carbon is thereby caused to unite with the oxygen of the zinc oxid. and the zinc is volatilized and passes off through the openings 18 18 to the tlues 19 19, which lead to a suitable combustion-chamber in which the volatile zinc is burned in air to form zinc-oxid fumes. As above described, these fumes are then passed through a bag-room, in which the zinc oxid is collected. The residues remaining in the reduction-chambers after the distillation of the zinc are dropped through the openings 16 16 in the bottoms of thl chambers 12 l2, when they may be 'removed in suitable tramcars running in the tunnels 13 13. '1`he residues removed from the chambers contain such impurities as may have been present in the zinc ores, in addition to gold, silver, and lead.

It will be seen that by the arrangement shown the ores to be treated are passed through the furnace in a practically vertical line. This facilitates the handling of the materials for the reason that the reductionchambers may be charged from an elevated railway or suitabiyplaced hoppers. The residues are removed from the reductionchambers largely b v action of the force of gravity.

The furnace is adapted for the burning of zinc as distilled off, as distinguished from furnaces of the prior art, in which the charge By this means 1 am enabledto save lead or silver which may be present in the ores.

The furnace is particularly useful for the direct production of zinc oxid, as distinguished from the practice of the prior art, in which IOO IIO

y 799,745 y i i a zinc has been distilled off and condensed to form spelter, the `spelter being afterward burned to form oxid.

"hile I have described the operation of my improved furnace as carried on in the production of zinc oxid, it will be apparent that it may be used forinanyT other purposes such, for instance, as the production of lead oxid.

Many other Inodilications and changes will be apparent to those skilled in the art, and I do not, therefore, wish to limit myself to the precise disclosure herein set forth; but,

Having described my invention, l claim as new and desire to secure by Letters Patent- 1n a metallurgical furnace comprised in a unitary structure, the combination with parallel passages or chambers extending longitudinally along the center of the furnace, regenerative furnaces extending longitudinally along the sides. of the furnace, passage-ways connecting the regenerative furnaces with the parallel chambers, partitions between the chambers, each partition being hollow to form a left and right reductionchamber having thin walls, oxidizing-chambers extending longitudinally over the regenerative furnaces, one at each side of the structure, passageways connecting the left reduction-chambers with the left oxi(lizing-chamber, passage-ways connecting the right reduction-chamber with the right oxidizing-chamber, an opening in the top of each reduction-chamber for receiving the products to be treated, a passageway below each row of reduction-chambers, and a trap-door 15 at the bottom of each re duction-clmmbor by means of which the prod-v ucts of each of the reduction-chambers may bc conveyed to each of the passage-ways be` low the reduction-chambers.

In witness whereof I hereuntosubscribe my name this 24th day of March, A. l). 1903.

. llllhll ALEXAXDER MACKAY. ritnessesz A. RASMUSSEN, ED. NELSON. 

